The present invention generally relates to the filtration of a contaminated gas stream. More particularly, the present invention is directed toward a filter system utilizing a modular filter element having a coalescing section which filters out and coalesces contaminants from a gas stream in order that the contaminants may drain from the filter.
To decontaminate a gas stream, conventional filter systems utilize a filter element having an end cap positioned so that drainage of the coalesced contaminants occurs either through the end cap or along an outside edge of the end cap.
A particular filter element currently in use includes an end cap chemically bonded to the element and having a portion located exterior to all of the remaining elements within the end cap. In this arrangement, contaminants coalesce and drain from the gas stream. Through gravity, the coalesced contaminants drip into the end cap. When enough contaminants drip into the end cap, eventually the contaminants will spill over and drip down the exterior of the end cap portion.
Deficiencies exist with this conventional arrangement. One deficiency is that the contaminants create a slick and messy surface on the end cap, hampering replacement of the filter element. Without a non-stick surface, removing such a filter element from a filter system is made more difficult.
Another conventional arrangement includes a filter element having an end cap with a plurality of slots provided therein to allow for drainage of coalesced contaminants through a lower surface of the end cap. An example of such an arrangement may be found in United Kingdom Patent Application 2,261,830.
Deficiencies exist in this arrangement. The end cap described in UK Patent Application 2,261,830 must be formed with greater lateral dimensions, which makes manufacture of the filter element more expensive and may interfere with the close tolerances required in conventional filter system vessels.
Another deficiency with existing drain layer materials is the ability to drain high concentrations of liquid contaminant without re-entraining said contaminant. The liquid drainage rate is limited by the structure of the existing materials. The ultimate filtration capacity and efficiency are directly effected by the drainage capacity.